/*
 * Copyright 2007 Matt Jensen
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */
package org.jtell.config;

/**
 * <p>
 * <code>OrderMetadata</code> defines the public interface to an order metadata object. Implementors hold information on
 * a single event listener order entry.
 * </p>
 */
public interface OrderMetadata
{
    /**
     * <p>
     * Get the order polarity, <em>after</em> or <em>before</em>.
     * </p>
     *
     * @return {@link OrderType} instance.
     */
    OrderType getOrderType();

    /**
     * <p>
     * Get the order token string.
     * </p>
     *
     * @return {@link String} order token string.
     */
    String getToken();

    /**
     * <p>
     * Flag indicating whether the token is required. If the token is required but is not contributed by another in the
     * set of listeners to be notified of a given event, the listener associated with this order entry will not be
     * invoked. 
     * </p>
     *
     * @return <code>boolean</code> <code>true</code> if the token is required.
     */
    boolean isRequired();
}
